package jdbc;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Optional;

public class JDBCDemo6 {
    public static void main(String[] args) {
        try (
                Connection connection = DBUtil.getConnection();
        ){
            Statement statement = connection.createStatement();
            String sql = "SELECT COUNT(*) count,c.name "+
                    "FROM student s "+
                    "JOIN class c ON s.class_id = c.id "+
                    "GROUP BY c.name ";
            ResultSet rs = statement.executeQuery(sql);
            while (rs.next()) {
                int count = rs.getInt("count");
                String className = rs.getString("c.name");
                System.out.println(count + "," + className);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }


    }
}
